Zhuo Yizhi, Xia Zhijie, Qi Yuan, Sumigawa Takashi, Wu Jianyang, Šesták Petr, Lu Yinan, Håkonsen Verner, Li Tong, Wang Feng, Chen Wei, Xiao Senbo, Long Rong, Kitamura Takayuki, Li Liangbin, He Jianying, Zhang Zhiliang
NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China, Hefei, 230026, China.
Adv Mater. 2021 Jun;33(23):e2008523. doi: 10.1002/adma.202008523. Epub 2021 May 3.
Current synthetic elastomers suffer from the well-known trade-off between toughness and stiffness. By a combination of multiscale experiments and atomistic simulations, a transparent unfilled elastomer with simultaneously enhanced toughness and stiffness is demonstrated. The designed elastomer comprises homogeneous networks with ultrastrong, reversible, and sacrificial octuple hydrogen bonding (HB), which evenly distribute the stress to each polymer chain during loading, thus enhancing stretchability and delaying fracture. Strong HBs and corresponding nanodomains enhance the stiffness by restricting the network mobility, and at the same time improve the toughness by dissipating energy during the transformation between different configurations. In addition, the stiffness mismatch between the hard HB domain and the soft poly(dimethylsiloxane)-rich phase promotes crack deflection and branching, which can further dissipate energy and alleviate local stress. These cooperative mechanisms endow the elastomer with both high fracture toughness (17016 J m ) and high Young's modulus (14.7 MPa), circumventing the trade-off between toughness and stiffness. This work is expected to impact many fields of engineering requiring elastomers with unprecedented mechanical performance.
目前的合成弹性体存在众所周知的韧性和刚度之间的权衡问题。通过多尺度实验和原子模拟相结合，展示了一种同时具有增强韧性和刚度的透明无填充弹性体。所设计的弹性体包含具有超强力、可逆和牺牲性八重氢键（HB）的均匀网络，在加载过程中将应力均匀分布到每个聚合物链上，从而提高拉伸性并延迟断裂。强氢键和相应的纳米域通过限制网络流动性来提高刚度，同时在不同构型之间转变时通过耗散能量来提高韧性。此外，硬氢键域和富含聚二甲基硅氧烷的软相之间的刚度不匹配促进了裂纹偏转和分支，这可以进一步耗散能量并减轻局部应力。这些协同机制赋予弹性体高断裂韧性（17016 J/m²）和高杨氏模量（14.7 MPa），规避了韧性和刚度之间的权衡。这项工作有望影响许多需要具有前所未有机械性能的弹性体的工程领域。
